You are here
Botanical Name – Acer ginnala
Botanical Name – Acer ginnala
Common Name – Amur Maple
Photo provided by Cat Nelson, from the NC Arboretum collection
Native to – Northern China, Manchuria and Japan
Botanical Information – Acer ginnala as it has been called since Carl Maximowicz, a Russian botanist in 1857, first described it. Technically, today it is considered a subspecies of Acer tataricum (Acer tataricum subsp ginnala) but its name has been in use for so long Acer ginnala will probably stick to this plant forever. This is considered a large shrub or occasionally a small tree to 30 feet when it is grown in the ground. The leaves are 3-lobed with some being unlobed on the same plant and there are always some white and pinkish variegated leaves. The variegation is mostly limited to very small blotches or streaks which are not noticeable unless you really look for them.
General – Acer ginnala is an excellent subject for making into bonsai. Its leaves are small normally and with bonsai cultural techniques can be made to be quite small and delicate. The leaves are dull to dark green and sometimes are mottled with white and pink spots. Autumn coloring can be a brilliant red but will vary with each individual tree. The bark is a nice light gray that contrasts well with the darker green leaves. If you’re lucky enough to have the tree flower it will produce winged fruits (seeds) that will turn red while the leaves are still green making for an interesting contrast. From a bonsai perspective this tree has all the great characteristics that you want in a deciduous tree. It buds back to old wood easily and can be drastically root pruned without any detrimental affects to the tree. In addition, this tree is very cold hardy and is bothered by few if any pests.
Cultivars – Flame – Generally available now in the nursery trade as a landscape tree. Durand’s Dwarf – A very desirable dwarf but very difficult to find.
For bonsai, full morning sun with light shade in the afternoon is best. Container or ground grown stock can be grown in the full sun all day.
Acer ginnala is extremely cold hardy and requires little if any protection during the winter in Zone 5 and higher. In Zones below 5 minimal protection, in the form of pine needles, snow cover or a cold frame, are more than adequate for this little guy.
All maples like to have constant moisture and Acer ginnala is no different. Even moisture should be applied to this plant year around. Protection from the drying effects of winter should be considered also.
Your fertilizing program should begin as soon as the buds begin to swell in the spring and continue through the growing season. A good general purpose fertilizer applied at the recommended dosage is just fine. If you’re on a diluted fertilizing program appropriate adjustments should be made to the amount and frequency that fertilizer is applied.
For finished bonsai pruning for ramification should be done from leaf out until the end of the growing season (usually at the onset of hot summer weather). Let 3 to 4 leaf nodes grow out and then cut them back to the first set of buds. All major pruning should be done in the fall after leaf drop. For trees in training pruning can be done at almost any time except in the early spring when maples are subject to excessive bleeding.
Wiring Amur maple should be done just as the tree looses its leaves in the fall. It is this period of the season that the branches are still pliable before the onset of winter when the tree expels water from the branches, making them brittle and subject to breakage. Wire can be maintained on the tree until it buds out in the spring which is when it should be removed. Of course you can wire this tree during the growing season but if you’re not careful it may girdle.
For young trees repotting and root pruning should be done every 1 or 2 years. For older established trees it can be as long as every 3. No matter how old the tree is the roots should be inspected every spring before the buds swell. This will allow one to evaluate not only whether the tree should be repotted but more importantly the health of the roots. Timing should coincide with the onset of root growth which is long before the buds swell in the spring. Look for the tips of the roots to be white and actively growing and that will be your signal to get on with the job.
Pests and Diseases
The types and number of pests and diseases will greatly depend upon your location and the spraying program that you have established for your trees. In general, the pests most commonly seen are Mites, Aphids, and Scale. Mites and Aphids can be controlled with commonly available insecticidal sprays using the recommended methods that come with the product. For those who don’t like to use insecticidal sprays these pests can be kept under reasonable control by using a strong spray of water late in the day just before dark. Aphids tend to locate themselves at the soft new growth. Mites tend to be on the underside of the leaves at the leaf veins. Scale can appear both during the summer and winter months and appear at branch junctions and are sometimes difficult to notice. A sure sign of aphid and scale infestation is the appearance of ants on your trees. The best recommendation that can be made is to develop a relationship with your local Department of Agriculture or Entomology agents to get familiar with the pests in your particular area.
Propagation of the species is by seed. The cultivars are either grafted or cutting grown.
Seed - stratify for 90 days at 38 degrees F prior to planting.
Grafting – Root stock should be brought into the greenhouse in early February and grown until it leafs out. Once the root stock is growing scions should be collected from dormant plants and grafting can take place. Most common method is a side veneer graft. Summer approach grafting may also be done.
Cuttings - Summer cuttings will give the best results.